JSON.stringify replacer function for having object keys sorted in output (supports deeply nested objects)

JSON.stringify-replacer-sort-keys.js

// Spec http://www.ecma-international.org/ecma-262/6.0/#sec-json.stringify
const replacer = (key, value) =>
	value instanceof Object && !(value instanceof Array) ? 
		Object.keys(value)
		.sort()
		.reduce((sorted, key) => {
			sorted[key] = value[key];
			return sorted 
		}, {}) :
		value;

// Usage

// JSON.stringify({c: 1, a: { d: 0, c: 1, e: {a: 0, 1: 4}}}, replacer);